The present invention relates to an airbag device which is suitable for a passenger seat of an automobile, and especially, the present invention relates to an airbag device in which a connection structure between a lid and a case is improved.
In a passenger's seat airbag device, a folded airbag is accommodated in a case, that is also called as a container or retainer, and a rim portion of a gas receiving hole of the airbag is attached to the case.
A front surface of the case is opened, and this opening is covered by a lid. The lid is disposed on a substantially same plane as an instrument panel. When an inflator disposed in the case is actuated to generate a gas, the airbag presses a reverse side of the lid to open the lid, and the airbag is deployed in an interior of the vehicle.
Incidentally, leg portions project downwardly from the reverse surface of the lid, and the leg portions are attached to the case by rivets or bolts in most cases. A tear line may be provided in the lid in order to open the lid in case of deploying the airbag, so that the lid is torn to open along the tear line. Also, the lid may be opened by separating the leg portions from the case. The lid may be opened by tearing the leg portions.
Further, in many cases, hook fittings are welded to the case, and hook portions of the hook fittings are inserted into openings in the leg portions.
FIG. 3 shows a sectional view showing a conventional airbag device in which the hook fittings are applied. An airbag device 1 is formed of an inflator 2 for generating a gas in the event of a vehicle collision; a case 3 for accommodating the inflator; an airbag 5 accommodated inside the case 3 in a folded condition; and a lid 6 for closing an opening at an upper portion of the case 3. Reference numeral 9 designates an instrument panel.
On an outer surface of the upper portion of the case 3, hook fittings 10 and 11 are fixed by spot welding. The hook fittings 10 and 11 extend along an upper rim of the case 3, and a plurality of hook portions 12 in a claw shape is integrally formed with an adequate interval therebetween in a direction of extending the hook fittings 10 and 11. In leg portions 7 of the lid 6, there are formed openings 13 which correspond to the hook portions 12 and engage the hook portions 12. On an inner surface of the lid 6, a thin-walled portion 8 is formed.
In order to attach the lid 6 to the case 3 for assembling the airbag device 1, the lid 6 is pushed inwardly to cover the opening at the upper surface of the case 3. As a result, the leg portions 7 of the lid 6 are deformed elastically outwardly and passes over the hook portions 12, and when the hook portions 12 and the openings 13 are aligned, the leg portions 7 are returned to the original shapes, so that the hook portions 12 are inserted into the openings 13.
In the airbag device structured as described above, when the inflator 2 is actuated, the airbag 5 is inflated, and the lid 6 is torn to open along the thin-walled portion 8, so that the airbag 5 is deployed in the interior of the vehicle.
As a conventional structure of attaching the leg portions of the lid to the case, Japanese Patent Publication (KOKAI) No. H9-277897 discloses a structure in which projections are provided on an inner surface of a rim of the case in order to engage the openings in the leg portions with the projections, and the leg portions are pressed against the inner surface of the case by end portions of fittings inside the case called diffusers.
In case the leg portions 7 are engaged with the hook portions 12 of the hook fittings 10 and 11 as shown in FIG. 3, it is necessary to bend the leg portions 7 largely outwardly. Thus, in the assembling step of attaching the lid 6 to the case 3, it is necessary to press the lid 6 against the case 3 strongly, resulting in a disadvantage in the assembling.
Also, in the structure disclosed in Japanese Patent Publication (KOKAI) No. H9-277897, it is necessary to extend the end portions of the diffusers up to the vicinity of the rim of the front surface of the case. As a result, the device becomes considerably heavy.
Accordingly, an object of the invention is to provide an airbag device which is easy to assemble and has a lid attaching member with a light weight.
Further objects and advantages of the invention will be apparent from the following description of the invention.